Within packaging technology where a packaging container is formed from a packaging laminate, it is known to provide the packaging laminate as a web which prior or during packaging is formed to the packaging container. Guiding marks, e.g. for optical reading has been provided to guide operations when finishing the package, such as forming, sealing, folding, etc. Such guiding marks are sometimes referred to as register marks. The register mark for optical reading is provided during printing of the packing laminate, where e.g. decoration or product information is printed on the packaging laminate. A problem with such register marks is that they consume a non-negligible area of what becomes the exterior of the package. A further problem is that such a register mark has to rely on the printing being well aligned with other operations performed on the web. It is therefore a desire to provide an improved provision of marking of web of packaging laminate. A solution to these and other issues have suggested by the present applicant in the form of the provision of magnetic marking of packaging material. Such solutions have been disclosed in several patent applications. The present disclosure will relate to an improved device and method for magnetic marking, and a packaging material having been magnetised with such device and method. To that end the outcome of the present disclosure may be applied to existing schemes or magnetic marking, by providing an improved magnetic marking.